Low speed rotary fluid apparatus with elastic sealing liner

ABSTRACT

In a fluid apparatus for low speed continuous rotation having a rotor rotatable continuously within a cylinder, a tubular seal material of synthetic resin such, for example, as fluoric resin is fitted into the cylinder in contact with the inner periphery of the cylinder, the seal material is compressed axially by a pair of end covers closing the ends of the cylinder, and the movable rotor is provided with a square packing in contact with the inner peripheral surface of the seal material and the inner surfaces of the end covers. The seal material and the square packing cooperate with each other to provide complete sealing at corners of the contact surface within the cylinder preventing internal leakage of fluid within the cylinder.

United States Patent [191 Higuchi et a1. i

[ LOW SPEED ROTARY FLUID APPARATUS WITH ELASTIC SEALING LINER [75] Inventors: Yasuo Higuchi, Komaki; Yoshio Mitsumura, Gifu, both of Japan [73] Assignee: Chukyo Electric Co. Ltd.,

Komaki-shi, Aichi-ken, Japan [22] Filed: Nov. 29, 1972 [2]] Appl. No.: 310,267

[30] Foreign Application Priority Data Dec. 3, 1971 Japan 46-97186 [52] US. Cl 418/56, 418/61 A, 418/113, 418/142, 418/153, 418/178 [51] Int. CL... Flc 21/00, F040 /00, F04c 29/00 [58] Field of Search 418/56, 61, 113,119,142, 418/152,153,l56,104,178

[56] References Cited UNITED STATES PATENTS 2,966,860 l/l961 Maynard 418/178 3,155,313 11/1964 Bentele 418/178 3,190,183 6/1965 Walker et al. 418/152 3,193,188 7/1965 Bentele.... 418/142 3,251,541 5/1966 Paschke 418/61 A III [111 3,827,835 Aug. 6, 1974 3,270,717 9/1966 Gassmann et a1 418/61 3,359,951 12/1967 Sabet 418/142 FOREIGN PATENTS OR APPLICATIONS 1,426,016 12/1968 Germany 418/61 Primary Examiner-Carlton R. Croyle Assistant Examiner-John J. Vrablik Attorney, Agent, or FirmKurt Kelman [5 7] ABSTRACT In a fluid apparatus for low speed continuous rotation having a rotor rotatable continuously within a cylinder, a tubular seal material of synthetic resin such, for example, as fluoric resin is fitted into the cylinder in contact with the inner periphery of the cylinder, the seal material is compressed axially by a pair of end covers closing the ends of the cylinder, and the movable rotor is provided with a square packing in contact with the inner peripheral surface of the seal material and the inner surfaces of the end covers. The seal material and the square packing cooperate with each other toprovide complete sealing at corners of the contact surface within the cylinder preventing internal leakage of fluid within the cylinder.

6 Claims, 6 Drawing Figures PATENTEU M13 SHEET 3 OF 4 PAIENIEmus 6l974 SHEET 4 OF 4 The present invention relates to a fluid apparatus for low speed continuous rotation, and more particularly,

to a fluid apparatus for low speed continuous rotation for continuously rotating a rotor within a cylinder or for delivering fluid by rotation of the rotor.

Generally, in a fluid apparatus such as a motor or a pump for continuously rotating a rotor in low speed by fluid pressure, a complete sealing between the rotor and the cylinder is needed since no leakage of the fluid is permitted. In the sealing apparatus of prior arts, however, it has been impossible to provide a complete sealing between the rotor and the cylinder. Accordingly, the technical idea to adopt a mechanism for applying fluid pressure directly to the rotor in a fluid apparatus such as pump or motor has been kept out of the actual use. Therefore, the fluid apparatus of prior arts has such disadvantages that the construction is very complicated and the torque produced by such apparatus is very small.

While a so-called rotary piston type fluid apparatus in which the cylinder is formed according to trochoidal curve and the rotor is rotated on the inner envelope thereof has such advantages that the construction is simple and it can produce larger torque, it has been very difficult to put such fluid apparatus into practical application since the sealing apparatus of the prior arts cannot provide a sufficient sealing between the rotor and the cylinder.

Accordingly, the primary object of the present invention is to provide a fluid apparatus for low speed continuous rotation having a sealing apparatus capable of preventing almost completely the leakage between the rotor and the inner surface of the cylinder even when a fluid pressure is applied directly to the rotor.

Another object of the present invention is to provide a fluid apparatus for low speed continuous rotation which is simple in construction, easy to manufacture and has a very high sealing property.

In order to accomplish these and other objects, the fluid apparatus for low speed continuous rotation is formed by providing a tubular seal material of synthetic resin in contact with the inner peripheral surface of the cylinder and compressing the sealing material in the axial direction by end covers closing the ends of the cylinder.

The invention will be better understood from the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a side sectional view of a fluid apparatus for low speed continuous rotation according to the present invention;

FIG. 2 is a front view of the apparatus with the end cover at right side (FIG. 1) removed;

FIG. 3 is a sectional view taken along the line III-III of FIG. 1 and seen from the direction of arrows;

FIG. 4 is a sectional view taken along the line IV-IV of FIG. 1 and seen from the direction of arrows;

FIG. 5 is a sectional view taken along the line V-V of FIG. 2; and

FIG. 6 is a fragmentary enlarged sectional view of FIG. 5 showing the corner formed by the seal material, square packing and end cover.

Referring now to FIGS. 1 3, there is shown a fluid apparatus for low speed continuous rotation according to the present invention generally designated 1 having a casing 2, a shaft means 4, and a rotor 5. A tubular cylinder body 20 of the casing 2 has an inner peripheral surface 21 formed by a two-joint trochoidally curved surface. At both ends of the cylinder body there are respectively fixed end covers 22 and 23 by suitable means such as bolts (not shown). At the center of the end cover 22 there is provided a stepped bearing hole 24 for receiving a shaft to be hereinafter described, and at the circumference of the bearing hole there are formed mutually spaced annular grooves 25 and 26 which are communicated respectively with an inlet port 27 and an outlet port 28 provided at the end cover 22 as shown in FIG. 4. At the center of the end cover 23 there is provided an opening 29 at the position corresponding to the bearing hole 24 of the end cover 22, and within the opening there is fitted a bearing support 30 having a stepped bearing hole 31 at the center thereof. The bearing support 30 is fixed to the end cover 23 by suitable means such as bolts (not shown). An end (the right end in FIG. 1) of the bearing support 30 protrudes axially within a cylinder chamber A by the predetermined length and on the outer peripheral surface of the protruded end is formed a gear 32.

Within the cylinder body 20 there is fitted a tubular sealing member 34 of synthetic resin such, for example, as nylon or fluoric resin having the shape same as that of the inner peripheral surface of the cylinder and in contact with the inner peripheral surface 21. The sealing member 34 which is a little longer than the cylinder itself is beforehand worked precisely so that the angle fonned by the inner peripheral surface 35 and the end faces 36a, 36b is accurately right-angled and that the edge is not made round, and, as a result, when the end covers 22 and 23 are fixed to the cylinder body 20, the sealing member 34 is compressed in the axial direction and the corner formed by the inner peripheral surface 35 of the sealing member 34 and the inner surface of the end cover is not made round.

The shaft means 4 comprises an eccentric shaft wherein the axis of journal portions 40 and 41 and the axis of a rotor support 42 provided between the journal portions 40 and 41 are not co-axial. The eccentric shaft is supported rotatably with respect to the casing by bearings 38 and 39 fitted respectively into larger diameter hole portions 24a and 31a of the bearing holes of the end covers 22 and the bearing support 30. On the outer peripheral surface of the rotor support of the shaft means or eccentric shaft 4 there are provided semiannular grooves 43a and 43b separated from each other by a pair of projections 44a and 44b. At the center of the eccentric shaft 4 there are provided a pair of fluid passages 45a and 45b extending axially which are respectively at an end communicated to the grooves 43a and 43b respectively through passages 46a and 46b. The other ends of the passages 45a and 45b are sealed respectively by plugs 47a and 47b. The passage 45a is communicatable with the outer periphery of the journal, namely the annular groove 25 through an axially extending passage 48a provided at the position corresponding to the annular groove 25 provided at the end cover 22, and similarly, the passage 45b is communicatable with the outer periphery of the journal, namely the annular groove 26 through an axially extending passage 48b provided at the position corresponding to the annular groove 26 formed at the end cover 22.

At the outer periphery of the rotor support 42 of the eccentric shaft 4 there is fitted a sleeve 51 of the rotor 5 rotatably by and with respect to the eccentric shaft 4. The inner diameter of the rotor sleeve 51 is larger at the bearing support side and on the inner peripheral surface thereof there is provided an internal gear 52 for meshing with a gear 32 provided at the bearing support 30. On the outer surface of the rotor sleeve 51 there is fitted a cylindrical sealing member 53 of elastic synthetic resin such, for example, as urethane rubber or fluoric resin. Further on the outer surface of the sealing member 53 there is fitted, as shown in FIG. 3, a rotor member 54 the section of which is substantially a triangle. The rotor member 54 is divided into three portions 54a, 54b, and 540 at each vertices. The rotor portions 54a, 54b, and 540 are provided at each one of the joint surfaces respectively with rectangular projections 55a, 55b, and 550 as shown in FIGS. 3 and 5, and on the outer peripheries of the projections there are respectively fitted square packings 56a, 56b, and 560. The rotor portions 54a, 54b, and 54c are joined respectively with the adjacent rotor portions by a plurality of pins 57 and further with the rotor sleeve by a plurality of pins 58. The rotor 5 has such a construction that at each vertex the square packings 56a, 56b, and 560 are always in contact with the inner surface 35 of the sealing member within the cylinder. Accordingly, the rotor is supported on the eccentric shaft 4 rotatably with respect thereto within the cylinder chamber A so that the rotor sleeve 51 and the rotor member 54 are in one unit and the square packings 56a, 56b, and 56c are always in contact with the inner surface 35 of the sealing member and the inner surface of the end cover.

At the intermediate portions of the vertices of the rotor there are respectively provided at the positions corresponding to the grooves 43a, 43b of the eccentric shaft with passage ports 59a, 59b, and 59c extending radially for communicating the grooves 43a or 43b with the outside of the rotor. Accordingly, feeding and exhaust of fluid to and from the cylinder chamber portion a defined by the rotor portion 54c, square packings 56b, 56c, sealing member 34, and end covers 22, 23 is made through the passage port 59c, feeding and exhaust of fluid to and from the cylinder chamber portion a" defined by the rotor portion 54a, square packings 566, 56a, sealing member 34, and end covers 22, 23 is made through the passage port 59a, and feeding and exhaust of fluid to and from the cylinder chamber portion a' defined by the rotor portion 54b, square packings 56a, 56b, sealing member 34, and the end covers 22, 23 is made through the passage port 59b.

The operation of the low speed continuous rotation apparatus according to the present invention will now be described with the aid of the Figures.

The fluid flowing in from the inlet port 27 (FIG. 4) is directed through the annular groove 25, passage 48a, passage 45a and passage 46a into the groove 43a formed on the outer periphery of the eccentric shaft, and then introduced into the cylinder chamber portion a through the passage 590. The fluid introduced into the cylinder chamber portion a acts on the outer surface of the rotor portion 540 to rotate the rotor in the clockwise direction on the eccentric shaft keeping the rotor in contact with the inner surface of the sealing member 34 and to rotate the eccentric shaft 4 in the clockwise direction. On the other hand, the fluid within the cylinder chamber portion a" is discharged outside from the outlet port 28 through the passage port 59a, groove 43b, passage 46h, passage 45h, passage 48b, and annular groove 26.

Then, when the eccentric shaft 40 is rotated by l, the rotor 5 takes the position shown in broken line in FIG. 2. In this position, since the groove 43a communicated with the inlet port 27 is communicated with the cylinder chamber portion a" through the passage port 490, the fluid flows into the cylinder chamber portion a" to act on the outer surface of the rotor portion 54a and to rotate the rotor in the clockwise direction. On the other hand, the fluid within the cylinder chamber portion a' is discharged from the outlet port 28 through the passage port 59b, groove 43b, passage 46b, passage 45b, passage 48b, and annular groove 26. At this time, since the passage port 59c is closed by the projection 44b, the fluid within the cylinder chamber portion a remains there without being discharged until the passage port 59c is again communicated with the groove 46b.

Thus, the rotor and the eccentric shaft continue rotation in the proportion of three turns of the eccentric shaft per one turn of the rotor.

The seal which is the characteristic of the present invention will now be described in detail.

The tubular sealing member 34 and the cylindrical sealing member 53 are, as described above, made of synthetic resin having high elasticity and superior sealing property, and the both end faces thereof are precisely worked so that the edge portions formed by the end portions and the inner peripheral surface or the outer peripheral surface will not be made round. The both end covers are polish-finished in the inner surface, and by these polish-finished inner surface the sealing members 34 and 53 are slightly compressed in the axial direction and assembled. The inner surface 35 of the sealing member 34, the outer surface of the sealing member 53, and the inner surfaces of the end covers 22 and 23 are polish-finished in the same degree of the slide contact surface with O-ring commonly used taking the surface roughness into consideration.

The square packings 56a, 56b, and 56c fitted into the projections of the rotor member are made of elastic material such, for example, as synthetic resin and serve to prevent leakage between these square packings and the inner surface of the sealing member 34, the inner surface of the end covers, and the outer surface of the sealing member 53. In this case, it is relatively easy to provide the sealing effect of the same degree as in the slide contact surface of commonly used O-rings except in the corner formed by the end covers 22, 23 and the sealing members 34, 53 which presents a difficult problem in sealing.

According to the present invention, since the end faces of the tubular sealing members 34 and 53 are precisely worked so that the edge formed by such end faces and the inner or outer peripheral surfaces is not made round but right-angled and since the sealing members are assembled in the manner that the end faces thereof are compressed in the axial direction, substantially complete sealing can be accomplished by working the square packings so that the corners thereof are not made round.

The experimental results are as follows. Since the radius R of the rounded portions of the edge of the square packings 56a, 56b, and 56c can be reduced, when made in combination molding die, as small as about 0.01 mm,

the clearance at the corner may be about 0.004 mm when such packings are used. When these square packings are assembled in the condition of actual use and compressed, the clearance can be further reduced as small as the surface roughness of the cylindrical surface 3.2S(JlS)'. Accordingly, the corner portion can 'be sealed in the same degree as in the other portion. The packings may not necessarily be square packings. Since the sealing members 34 and 53 are made of elastic material and compressed in the axial direction, even when the angle formed by the end covers 22, 23 and the inner or outer peripheral surfaces of the sealing members 34 and 53 is not precisely in a right angle, the sealing members can provide sufficient sealing effect in the normal direction to thereby enable smooth rotation of the rotor.

When the rotor is rotated, the point of the square packing in contact with the sealing member 34 is oscillated (oscillation angle However, the oscillation can be eliminated by suitable selection of the shape of the outer peripheries of the square packings, hardness of the material, and the rotating back-up ring.

While we have shown and described a specific embodiment of our invention practiced in rotary piston engines, it will be understood that the invention is not limited thereto but may be otherwise variously practices within the scope of the following claims. And, it will also be understood that the tubular sealing member may have section in any annular shape and not limited to the two-joint trochoidal curve type.

What we claim is:

l. A fluid apparatus for low speed continuous rotation, comprising in combination:

a casing having a tubular cylinder body and a pair of end covers for closing both ends of the cylinder body;

shaft means supported rotatably by the pair of end covers; and,

a rotor supported rotatably by and with respect to'the shaft means within the casing;

said fluid apparatus being provided with a tubular sealing member of elastic synthetic resin fitted onto the inner peripheral surface of the cylinder and packings fitted to said rotor and being in sealing contact with the inner peripheral surface of the sealing member and the inner surfaces of the end covers;

said tubular sealing member having the length a little larger than that of the cylinder body and being made so that the edge portion formed by the both end faces and the inner peripheral surface is not made round, whereby, when assembled, the sealing member is compressed in the axial direction by the pair of end covers. 2. A fluid apparatus for low speed continuous rotation according to claim 1, wherein:

said packings comprises square packings and is in sealing contact with the outer peripheral surface of the cylindrical sealing member fitted between the rotor sleeve and the rotor member. 3. A fluid apparatus for low speed continuous rotation according to claim 1, wherein:

said rotor has a rotor sleeve and a rotor member; said fluid apparatus is provided with a cylindrical sealing member of elastic synthetic resin fitted between the rotor sleeve and the rotor member; said cylindrical sealing member has the length a little larger than that of the cylinder body and is made so that the edge portion formed by the both end faces and the outer peripheral surface is not made round, whereby, when assembled, the cylindrical sealing member is compressed in the axial direction by the pair of end covers. 4. A fluid apparatus for low speed continuous rotation according to claim 1, wherein:

the inner peripheral surface of the cylinder body is formed by a two-jointed trochoidally curved surface; said rotor has a substantially triangular section; and

said packings are in sealing contact with the inner peripheral surface of the tubular sealing member at the vertices of the triangle of said rotor. 5. A fluid apparatus for low speed continuous rotation according to claim 4, wherein:

said shaft means comprises an eccentric shaft; and, said rotor is rotatable with respect to the eccentric shaft. 6. A fluid apparatus for low speed continuous rotation according to claim 4, wherein:

said rotor member is divided into three portions at the vertices of said triangle; and, said packings are fitted between the joint portions of the divided rotor. 

1. A fluid apparatus for low speed continuous rotation, comprising in combination: a casing having a tubular cylinder body and a pair of end covers for closing both ends of the cylinder body; shaft means supported rotatably by the pair of end covers; and, a rotor supported rotatably by and with respect to the shaft means within the casing; said fluid apparatus being provided with a tubular sealing member of elastic synthetic resin fitted onto the inner peripheral surface of the cylinder and packings fitted to said rotor and being in sealing contact with the inner peripheral surface of the sealing member and the inner surfaces of the end covers; said tubular sealing member having the length a little larger than that of the cylinder body and being made so that the edge portion formed by the both end faces and the inner peripheral surface is not made round, whereby, when assembled, the sealing member is compressed in the axial direction by the pair of end covers.
 2. A fluid apparatus for low speed continuous rotation according to claim 1, wherein: said packings comprises square packings and is in sealing contact with the outer peripheral surface of the cylindrical sealing member fitted between the rotor sleeve and the rotor member.
 3. A fluid apparatus for low speed continuous rotation according to claim 1, wherein: said rotor has a rotor sleeve and a rotor member; said fluid apparatus is provided with a cylindrical sealing member of elastic synthetic resin fitted between the rotor sleeve and the rotor member; said cylindrical sealing member has the length a little larger than that of the cylinder body and is made so that the edge portion formed by the both end faces and the outer peripheral surface is not made round, whereby, when assembled, the cylindrical sealing member is compressed in the axial direction by the pair of end covers.
 4. A fluid apparatus for low speed continuous rotation according to claim 1, wherein: the inner peripheral surface of the cylinder body is formed by a two-jointed trochoidally curved surface; said rotor has a substantially triangular section; and said packings are in sealing contact with the inner peripheral surface of the tubular sealing member at the vertices of the triangle of said rotor.
 5. A fluid apparatus for low speed continuous rotation accordiNg to claim 4, wherein: said shaft means comprises an eccentric shaft; and, said rotor is rotatable with respect to the eccentric shaft.
 6. A fluid apparatus for low speed continuous rotation according to claim 4, wherein: said rotor member is divided into three portions at the vertices of said triangle; and, said packings are fitted between the joint portions of the divided rotor. 